It's possible that two different servers can return the same (clientid,
verifier) pair purely by coincidence.  Both are 64-bit values, but
depending on the server implementation, they can be highly predictable
and collisions may be quite likely, especially when there are lots of
servers.

So, check for this case.  If the clientid and verifier both match, then
we actually know they *can't* be the same server, since a new
SETCLIENTID to an already-known server should have changed the verifier.

This helps fix a bug that could cause the client to mount a filesystem
from the wrong server.
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Tested-by: Yongcheng Yang <yoyang@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

xs_connect() contains an exponential backoff mechanism so the repeated
connection attempts are delayed by longer and longer amounts.

This is appropriate when the connection failed due to a timeout, but
it not appropriate when a definitive "no" answer is received.  In such
cases, call_connect_status() imposes a minimum 3-second back-off, so
not having the exponetial back-off will never result in immediate
retries.

The current situation is a problem when the NFS server tries to
register with rpcbind but rpcbind isn't running.  All connection
attempts are made on the same "xprt" and as the connection is never
"closed", the exponential back delays successive attempts to register,
or de-register, different protocols.  This results in a multi-minute
delay with no benefit.

So, when call_connect_status() receives a definitive "no", use
xprt_conditional_disconnect() to cancel the previous connection attempt.
This will set XPRT_CLOSE_WAIT so that xprt->ops->close() calls xs_close()
which resets the reestablish_timeout.

To ensure xprt_conditional_disconnect() does the right thing, we
ensure that rq_connect_cookie is set before a connection attempt, and
allow xprt_conditional_disconnect() to complete even when the
transport is not fully connected.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

If the layout stateid is already invalid, we have no work to do.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Address another memory leak.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Ensure that the layout state bits are synced when we cache a layout
segment for layoutreturn using an appropriate call to
pnfs_set_plh_return_info.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

We need to honour the NFS_LAYOUT_RETURN_REQUESTED bit regardless of
whether or not there are layout segments pending.
Furthermore, we should ensure that we leave the plh_return_segs list
empty.

This patch fixes a memory leak of the layout segments on plh_return_segs.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

When the layout state is invalidated, then so is the layout segment
state, and hence we do need to clean up the state bits.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

If we cannot grab the inode or superblock, then we cannot pin the
layout header, and so we cannot send a layoutreturn as part of an
async delegreturn call. In this case, we currently end up sending
an extra layoutreturn after the delegreturn. Since the layout was
implicitly returned by the delegreturn, that just gets a BAD_STATEID.

The fix is to simply complete the return-on-close immediately.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Amend the pnfs return on close helper functions to enable sending the
layoutreturn op in CLOSE/DELEGRETURN. This closes a potential race between
CLOSE/DELEGRETURN and parallel OPEN calls to the same file, and allows the
client and the server to agree on whether or not there is an outstanding
layout.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Add XDR encoding for the layoutreturn op, and storage for the layoutreturn
arguments to the DELEGRETURN compound.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Add XDR encoding for the layoutreturn op, and storage for the layoutreturn
arguments to the CLOSE compound.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

We need to account for the reply to the PUTFH operation in the
DELEGRETURN compound.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

The layoutreturn call will take care of invalidating the layout segments
once the call is successful.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

The parameter is already present in the "args" structure.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

There is no change to the value of NFS_LAYOUT_RETURN, so we should
not be waking up the RPC call.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Fix a potential race with CB_LAYOUTRECALL in which the server recalls the
remaining layout segments while our LAYOUTRETURN is still in transit.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

We may want to process and transmit layout stat information for the
layout segments that are being returned, so we should defer freeing
them until after the layoutreturn has completed.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Instead of grabbing the layout, we want to get the inode so that we
can reduce races between layoutget and layoutrecall when the server
does not support call referring.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Both pnfs.c and the flexfiles code have their own versions of the
range intersection testing, and the "end_offset" helper.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

We must put the task to sleep while holding the inode->i_lock in order
to ensure atomicity with the test for NFS_LAYOUT_RETURN.

Fixes: 500d701f ("NFS41: make close wait for layoutreturn")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

If there is an I/O error, we should not call LAYOUTGET until the
LAYOUTRETURN that reports the error is complete.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org # v4.8+

If the server sends us a completely new stateid, and the client thinks
it already holds a layout, then force a retry of the LAYOUTGET after
invalidating the existing layout in order to avoid corruption due to
races.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

We must ensure that we don't schedule a layoutreturn if the layout stateid
has been marked as invalid.

Fixes: 2a59a041 ("pNFS: Fix pnfs_set_layout_stateid() to clear...")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org # v4.8+

If we no longer hold any layout segments, we're normally expected to
consider the layout stateid to be invalid. However we cannot assume this
if we're about to, or in the process of sending a layoutreturn.

Fixes: 334a8f37 ("pNFS: Don't forget the layout stateid if...")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org # v4.8+

We must not call nfs_pageio_init_read() on a new nfs_pageio_descriptor
while holding a reference to a layout segment, as that can deadlock
pnfs_update_layout().

Fixes: d67ae825 ("pnfs/flexfiles: Add the FlexFile Layout Driver")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org # v4.0+

When initializing a freshly created slot for the calllback channel,
the seq_nr needs to be 0, not 1.  Otherwise validate_seqid
and nfs4_slot_wait_on_seqid get confused and believe that the
mpty slot corresponds to a previously sent reply.
Signed-off-by: Fred Isaman <fred.isaman@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

The NFS_INO_REVAL_FORCED flag needs to be set if we just got a delegation,
and we see that there might still be some ambiguity as to whether or not
our attribute or data cache are valid.
In practice, this means that a call to nfs_check_inode_attributes() will
have noticed a discrepancy between cached attributes and measured ones,
so let's move the setting of NFS_INO_REVAL_FORCED to there.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

If holding a delegation, we do not need to ask the server to return
close-to-open cache consistency attributes as part of the CLOSE
compound.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

If we're not closing the file completely, there is no need to request
close-to-open attributes.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

We don't need to ask for the change attribute when returning a delegation
or recovering from a server reboot, and it could actually cause us to
obtain an incorrect value if we're using a pNFS flavour that requires
LAYOUTCOMMIT.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

If we're reclaiming state after a reboot, or as part of returning a
delegation, we don't need to check access modes again.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Pull IOMMU fixes from David Woodhouse:
 "Two minor fixes.

  The first fixes the assignment of SR-IOV virtual functions to the
  correct IOMMU unit, and the second fixes the excessively large (and
  physically contiguous) PASID tables used with SVM"

* git://git.infradead.org/intel-iommu:
  iommu/vt-d: Fix PASID table allocation
  iommu/vt-d: Fix IOMMU lookup for SR-IOV Virtual Functions

Pull MIPS fixes from Ralf Baechle:
 "Another round of MIPS fixes for 4.9:

   - Fix unreadable output in __do_page_fault due to the KERN_CONT
     patchset

   - Correctly handle MIPS R6 fixes to the c0_wired register"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  MIPS: mm: Fix output of __do_page_fault
  MIPS: Mask out limit field when calculating wired entry count

Pull vfs splice fix from Al Viro.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fix default_file_splice_read()

Botched calculation of number of pages.  As the result,
we were dropping pieces when doing splice to pipe from
e.g. 9p.
Reported-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Pull i2c fixes from Wolfram Sang:
 "Here is a revert and two bugfixes for the I2C designware driver.

  Please note that we are still hunting down a regression for the
  i2c-octeon driver. While there is a fix pending, we have unclear
  feedback from the testers currently. An rc8 would be quite helpful
  for this case"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  Revert "i2c: designware: do not disable adapter after transfer"
  i2c: designware: fix rx fifo depth tracking
  i2c: designware: report short transfers